| Muscle energetics changes throughout maturation: a quantitative 31P-MRS analysis. | |
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MedLine Citation:
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PMID: 20847131 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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We quantified energy production in 7 prepubescent boys (11.7 ± 0.6 yr) and 10 men (35.6 ± 7.8 yr) using (31)P-magnetic resonance spectroscopy to investigate whether development affects muscle energetics, given that resistance to fatigue has been reported to be larger before puberty. Each subject performed a finger flexions exercise at 0.7 Hz against a weight adjusted to 15% of their maximal voluntary strength for 3 min, followed by a 15-min recovery period. The total energy cost was similar in both groups throughout the exercise bout, whereas the interplay of the different metabolic pathways was different. At the onset of exercise, children exhibited a higher oxidative contribution (50 ± 15% in boys and 25 ± 8% in men, P < 0.05) to ATP production, whereas the phosphocreatine breakdown contribution was reduced (40 ± 10% in boys and 53 ± 12% in men, P < 0.05), likely as a compensatory mechanism. The anaerobic glycolysis activity was unaffected by maturation. The recovery phase also disclosed differences regarding the rates of proton efflux (6.2 ± 2.5 vs. 3.8 ± 1.9 mM · pH unit(-1) · min(-1), in boys and men, respectively, P < 0.05), and phosphocreatine recovery, which was significantly faster in boys than in men (rate constant of phosphocreatine recovery: 1.3 ± 0.5 vs. 0.7 ± 0.4 min(-1); V(max): 37.5 ± 14.5 vs. 21.1 ± 12.2 mM/min, in boys and men, respectively, P < 0.05). Our results obtained in vivo clearly showed that maturation affects muscle energetics. Children relied more on oxidative metabolism and less on creatine kinase reaction to meet energy demand during exercise. This phenomenon can be explained by a greater oxidative capacity, probably linked to a higher relative content in slow-twitch fibers before puberty. |
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Authors:
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Anne Tonson; Sébastien Ratel; Yann Le Fur; Christophe Vilmen; Patrick J Cozzone; David Bendahan |
Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't Date: 2010-09-16 |
Journal Detail:
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Title: Journal of applied physiology (Bethesda, Md. : 1985) Volume: 109 ISSN: 1522-1601 ISO Abbreviation: J. Appl. Physiol. Publication Date: 2010 Dec |
Date Detail:
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Created Date: 2010-12-14 Completed Date: 2011-03-25 Revised Date: 2011-12-21 |
Medline Journal Info:
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Nlm Unique ID: 8502536 Medline TA: J Appl Physiol Country: United States |
Other Details:
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Languages: eng Pagination: 1769-78 Citation Subset: IM |
Affiliation:
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Centre de Résonance Magnétique Biologique et Médicale, UMR Centre National de la Recherche Scientifique 6612, Faculté de Médecine de Marseille, Université de la Méditerranée, Marseille, France. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Adenosine Triphosphate
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metabolism Adolescent Adult Child Creatine Kinase / metabolism Energy Metabolism* Glycolysis Hand Strength Humans Isometric Contraction* Kinetics Magnetic Resonance Spectroscopy* Male Middle Aged Muscle Development* Muscle, Skeletal / growth & development, metabolism* Oxidation-Reduction Phosphocreatine / metabolism Phosphorus Isotopes Recovery of Function Sexual Development* Young Adult |
| Chemical | |
Reg. No./Substance:
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0/Phosphorus Isotopes; 56-65-5/Adenosine Triphosphate; 67-07-2/Phosphocreatine; EC 2.7.3.2/Creatine Kinase |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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